Re: one axis closed loop control

Larry,

That is Model Engineer Workshop MEW; and I believe the US distributor
is Owl publications worldwide. They are online. The magazine is an
English (UK) publication.

Hope this helps.

Ballendo

P.S. It is sometimes available through Interlibrary Loan, and some
large university librarys have copies.

--- In CAD_CAM_EDM_DRO@y..., "ledinger" <ledinger@r...> wrote:
> How can one get NEW magazine?
> ----- Original Message -----
> From: "karl_l_townsend" <karl@c...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Wednesday, January 09, 2002 5:22 AM
> Subject: [CAD_CAM_EDM_DRO] one axis closed loop control
>
>
> > I've done a lot of study toward making a gear hobbing machine out
of
> > my CNC mill. Books by Colvin, Law, Barber-Coleman, and a very
> > interesting article in MEW magazine explain the gear hobbing
process.
> > Its one very versatile method of making almost any gear form.
> >
> > In very short summary, you can hob on a mill by mounting a hob
cutter
> > (I've been buying 'em up on Ebay) in the quill and rotating the
head
> > by the helix angle. You then need a driven 4rth axis to mount the
gear
> > blank in. This could be a rotary table mounted vertically, an
indexing
> > head or something similar.
> >
> > Then the hard part: Driving the 4rth axis. For many many years
this
> > was done with gearing. The Ivan Law book shows a complex method
to do
> > this with lathe change gears. Today, driving the 4rth axis is done
> > with a stepper motor in closed loop with an encoder on the
spindle.
> > Basically, the 4rth axis must rotate exactly one tooth for every
one
> > turn of the spindle. The MEW article ('Model Engineer's Workshop'
> > issue 75, July/August 2001) shows a method of building an encoder
and
> > stepper to drive the 4rth axis. This author must be a total
> > electronic type. He spent three pages describing how to build a
4rth
> > axis (the really easy part to understand, for me) and one
paragraph
> > and an electronic drawing showing how to closed loop drive a
stepper.
> > For me, I still have NO IDEA how to construct this.
> >
> > Right now, I'm building a 4rth axis with a D1-3 spindle nose and
worm
> > gear drive to a stepper motor. This can be used on my CNC mill for
> > many projects. My CNC control (Ahha Artisan) can drive a 4rth
axis,
> > but its open loop only, as nearly all PC based controls are.
> >
> > I've been watching for a method to closed loop drive this 4rth
axis.
> > So far, I've only got possibilities:
> >
> > 1. There is a closed loop control used on micro lathes for
threading.
> > It's called "The Frog" and is advertised in HSM magazine. But
> > you have to use his extremely small stepper - not enough beef
> >
> > 2. It looks like Parker Compumotor Inc. sells a stepper control to
> > drive a stepper based on an input shaft encoder. Looks very
spendy.
> > Haven't got a price quote yet.
> >
> > 3. Get someone in this NG to tell me how.
> >
> > Karl
> >
> >
> >
> > Addresses:
> > FAQ: http://www.ktmarketing.com/faq.html
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> >
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